Corrugated tube for rotary brushes



Oct. 22", 1963 R. F. TILGNER 3,107,381

CORRUGATED TUBE FOR ROTARY BRUSHES Filed July 1, 1959 3 Sheets-Sheet 1FICA F'|G.5

A3 Efi ,7 A r. V 49 Bio. a 49G 48 f? 5 4 R U 4m INVENTOR. RALPH A mam-.2

Oct. 22, 17963 R. F. TILGNER 3,107,381

CORRUGATED TUBE FOR ROTARY BRUSHES 5 Sheets-Sheet 2 Filed July 1, 1959I58 INVENTOR.

Oct. 22, 1963 R. F. TILGNER CORRUGATED TUBE FOR ROTARY BRUSHES 5Sheets-Sheet 3 Filed July 1, 1959 'FIO.I6

FIG. I3

FIGS

\ INVENTOR.

\ 24.41% A mom-a United States Patent 3,107,381 (IORRUGATED TUBE FQRRQTARY BRUSHES Ralph F. Tilgner, Ellicott (Iity, Md, assignor toPittsburgh Plate Glass Company, County of Allegheny, Pan, a corporationof Pennsylvania Filed July ll, 195$, Ser- No. 324,387 13 Claims. (Ql.-182) This invention relates to power-driven brushes and it hasparticular relation to mandrel structures for such brushes and to novelmeans for securing the several elements of the brush structure together.

Power-driven brushes have heretofore been formed by spirally windingupon a tubular cylindrical core or mandrel, a brush strip comprising achannel backing element having doubled fill material secured therein bymeans of a longitudinally extending filamentary locking core. Suchbrushes are relatively inexpensive to construct, but are characterizedby certain disadvantages, especially if operated under heavy loads and/or at high speeds. For example, the mandrels are often eitherexcessively heavy, cumbersome and expensive to form, or else they arelacking in rigidity against bending forces. Furthermore, the fillmaterial and the channel backing may tend strongly to overheat due tofrictional effect and/ or rapid flexing of the fill material. Suchoverheating is often detrimental to the fill material and/ or the coreor mandrel upon which the strip is mounted.

High speed operation of the brush also generates strong centrifugalforces, tending to distort the mandrel and to throw the brush strip orthe components thereof away from the mandrel. Such centrifugal force maybe so great as to cause detachment of the strip, in which instance itunwinds and may endanger personnel or equipment in the vicinity. Thisinvention comprises means for obviating the foregoing problem. Severalfeatures are involved and these often can be employed concurrently in asingle structure or can be employed individually in certain othercombinations. 7

One feature of the invention comprises the provision of a mandrel for aspirally wound brush strip, which mandrel is formed of a tube of sheetmetal, e.'g., steel, having a series of peripherally spaced corrugationsrunning longitudinally thereof. Such corrugations greatly enhance thestiffness of the mandrel to resist flexing movements exertedtransversely of the axis of the brush and do not add greatly to theweight of the construction.

As a second feature, the brush mandrel involves a novel bushingstructure comprising discs having teeth or tabs adapted to project intothe corrugations of the mandrel, whereby to provide a very strongdriving connection between the bushing and the mandrel.

As a third feature, the invention comprises the provision of a novelmethod of securing the mandrel shell to the adapter involving screws,preferably of the selfthreading type, adapted to be inserted through themandrel shell and correspondingly through coaxially extending flangesupon the adapter.

A fourth feature comprises the provision of a novel system of U-likeclamp elements, one or both legs of which are adapted to extend throughappropriate slots formed in the corrugations of the mandrel to embracethe brush strip wound upon the mandrel and having elements such asscrews or bolts, extending through its sides and engaging the side wallsof the channel backing element of the brush strip to hold the same inposition.

Sixthly, the invention comprises the provision of novel strap elementsfor attaching intermediate turns of the brush strip element to themandrel.

These and other features of the invention will be ap- A 3,lt?,38lPatented Oct. 22, 1963 parent from consideration of the drawings and thedescriptions thereof to follow.

lnthe drawings,

FIG. 1 is an isometric view of a presently preferred form of a mandrelstructure embodying the invention.

FIG. 2 is a plan view of a bushing adapted to be inserted in the mandrelshell disclosed in FIG. 1.

FIG. 3 is a sectional view substantially upon the line III-III of FIG.2. 1

FIG. 4 is a fragmentary detailed view of a clip element securing a brushstrip to a mandrel.

FIG. 5 is a second fragmentary detailed view of a form of clip which isof sufiicient width to grip two turns of the brush strip, whereby toform loops in the strip which are positively held from untwisting orloosening upon the mandrel.

FIG. 6 is a fragmentary sectional view through one of the clips, showingthe manner in which the shelf-threading screw therein bites into theedges of the channel member of the brush strip to lock same frommovement in the clip.

FIG. 7 is a fragmentary sectional view of a clip structure useful insecuring the intermediate turns of a brush strip to the mandrel.

FIG. 8 is a sectional view of one form of the mandrel structure, showingthe winding and the securing of the brush strip thereupon by welding.

FIG. 9 illustrates a modified form of sheet metal blank havingcorrugations formed therein, but being uncircularized and being adaptedfor use in forming a shell of the mandrel structure shown in FIG. 8.

FIG. 10 is a sectional view substantially upon the line X--X of FIG. 9'.

FIG. 11 is a plan view of a further modification of a corrugated sheetsuitable for use in forming the shells of rn'andrels.

FIG. 12 is a sectional view substantially upon the line XlIXlI of FIG.11.

FIG. 13 is a view partly elevation and partly in phantom of a brushconstructed in accordance with the provisions of the invention.

FIG. 14 is a sectional view showing a suitable fixture and the usethereof in assembling a brush in accordance with the provisions of thisinvention.

FIG. 15 is a fragmentary sectional view showing a portion of a rotarychuck suitable for use in winding a brush strip upon a mandrelconstructed in accordance with the provisions of this invention.

FIG. 16 is a sectional view substantially upon the line XVIXVI of FIG.13.

In the preferred embodiment of the invention as disclosed in FIG. 1, amandrel for a spirally wound brush is illustrated as comprising a shellor tube 20 formed of sheet metal with flutings or corrugations formed byridge or land portions 21 running longitudinally thereof. In thedrawing, the number of land portions is indicated as being nine, but anyother convenient number obviously could be employed. The land portionsare connected together by intermediate depressed web portions 22, whichare indicated as being connected to the side wall portions 23 of theland portions 21. The web portions are also indicated asbeing angularly'bent along lines 24 at their mid-portions, thus providing secondarycorrugations of approximately V-shape section-s. The shell or tubetherefore may be considered as being of polygonal section wherein curvedportions are obviated.

,Any convenient method may be employed in forming the various bends orangles the shell. For example, a blank of sheet metal such as iron orsteel may be passed between rollers having properly sectioned fiutingsthereupon. Also, the blanks of sheet metal may be subjected to apressing operation in a press having properly configured platens to formsingle units of the mandrel surface in a series of steps. Since the faceof the sheet is formed of a series of flat, longitudinally extendingstrips integrally joined along the several angles of the structure, thelatter method is suited for small scale operations where it is notconvenient to make up expensive special rollers or dies designed toshape the entire blank in a single step. This method is slower than thefirst method and involves more labor. However, the necessity ofproviding configured rollers or dies having repeating units of surfaceis obviated and a conventional metal bending press can then be used.

It is convenient in forming the several longitudinal bends in the sheetmetal blanks to effect the bends at such angles that the sums of theseveral bends will cause the metal to assume naturally an approximatecylindrical section so that when the bushings to be described areinserted therein, only slight bending will be necessary to attain thefinal shape. If desired, the angles or bends between the portions 23 andthe webs 22 may be approximately right-angular. The sums of the angles24 in the web portion will then provide the necessary bending of themetal approximately to obtain the desired perimeter of the shell.

Appropriate bushings for the shells are indicated at 26. These may beformed as annular members having internal and external flanges 27 and 28extending coaxially of the mandrel. The outer flange 28 may be slottedat one or more points around its perimeter, as indicated at 29, and theresultant tabs of sheet metal integral with the rear edge notch formedby slots 29 are bent radially outwardly as indicated at 31, providingteeth or keys spaced to seat within corrugations 21 in order to securethe bushing from rotation within the shell 20. Obviously, teeth might beprovided for each land around the circumference of the shell, though inthe drawings, a pair of teeth are shown and these are disposed incontiguous lands or cor rugations.

It will be apparent from the drawings and notably from FIGURE 2, thatthe teeth substantially correspond in dimensions to the transversesectional dimensions of the corrugations.

This construction has advantages in assembly, inasmuch as the spacingbetween contiguous lands 21 will vary but slightly and, therefore, agood fit between the lands and the teeth can readily be obtained withoutthe necessity of springing the metal forming the sheet. In event thatthere should be slight variations in the dimensions of the lands, theaccumulation of errors around the perimeter is obviated. Good fitbetween the shell and the bushings is thus obtained at all times.Winding of the corrugated sheet forming the shell about the bushing isalso facilitated.

It will be observed that a portion of the side wall and the inner flangeof the bushing in the shell may also be cut out as indicated at 32, toprovide a key-way in which a key may be inserted, providing means forsupporting and driving the mandrel upon a shaft or arbor.

Substantially any number of bushings may be provided in the shell andsuch number will depend upon the length of the mandrel, the gauge of themetal employed and the stresses to which the mandrel is likely to besubjected in service. In many instances, a pair of bushings will besufficient. These may be disposed at the ends of the shell, or may bespaced inwardly therefrom. In event that conditions require the same,one or more intermediate bushings, such as the one indicated at 33 inFIG. 1, may be employed.

The end portions of the metal forming the shell are indicated asoverlapping as at 34. The shell may be held in assembled relationshipupon the flanges of the bushing elements by appropriate means as, forexample, by one or more straps 36 of sheet metal, such as sheet steel.As many such straps as may be desired may be employed, though in FIG. 1the number is limited to one. These straps are of the conventional typeemployed as ties in holding bales or bundles together. The ends 37 ofthe straps overlap in conventional manner and are held together as bysimple seal elements 38, which may be clipped or crimped in well-knownmanner as indicated at 39, in order securely to hold the straps inplace.

These straps (sold as Signed steel strapping) and the seals therefor maybe employed as the binding for the mandrels. These materials arecommercial products which can be obtained at small expense. Also, theconventional stretcher and sealer units required for tightening thestraps and for applying the seals to hold the ends of the straps frommovement, may be used with little or no modification. Needless to say,other types of strapping and seals, and other apparatus for stretchingthe straps and applying the seals may be employed.

The straps, if desired, may be permanently retained and when soemployed, they add substantially to the strength of the structure andthus constitute safety features. The relative thinness of the strapspermits the brush strip material to be spirally wound upon the mandrelwith out appreciable distortion from the general section of the brushwhen the strip crosses or is superposed upon the strapping.

It is also permissible, if so desired, to remove the straps from theshell 23 after the other fastenings to he described have been disposedin place.

Various means to secure the overlapped end portions of the shell 2%} maybe employed. For example, the ends may be secured together by spotwelding. It is also permissible to secure said portions together byrivets, by bolts, by nails or by screws. Self-threading screws ofwellknown type are to be preferred because of economy and ease ofinsertion. Such screws are indicated at 41'. These screws, if desired,may also penetrate the flanges 28 of the bushing elements, whereby tosecure the ends of the blanks forming the shell to the bushing. Screwsmay be employed to secure the ends of the blank to each bushing. Ifdesired, additional screws may also be employed securing the ends of theblanks together intermediate of the bushings.

The strapping about the shell, together with the teeth 31 upon thebushing, may be relied upon as the sole securing means holding theshells in assembled relation upon the bushing and maintaining the shellfrom slippage upon the mandrel. However, it is often preferred to employadditional screws around the perimeter of the shell, penetrating theshell as at '42, intermediate of the lands 21 and penetrating theflanges 28, thus securing all of the bushings rigidly in place.

A conventional brush strip suitable for winding upon the shell isindicated at 43. This strip comprises a channel backing 44 havingdoubled fill material 46 such as fibers of Tampico, nylon or the like,disposed therein and being held in place by a filamentary core 47disposed in the bight portion of the fill. This brush strip is spirallywound upon the mandrel in well-known manner. However, in the windingoperation, an advantage results from the corrugation or fluting of theshell element of the mandrel, inasmuch as the backing element of thestrip in spanning between the lands 21 is caused to bend, forming slightangles at the corners of the lands. As a result, the turns of strip asthey are wound upon the mandrel, assume the form of a polygon. This doesnot appreciably affect the brushing characteristics of the assembledbrush, but is of advantage inasmuch as it reduces the tendency of thebrush to rotate or slip upon the mandrel and tends to reduce thestresses which are placed upon the clip elements or other fasteningdevices employed in securing the backings of the brush strip upon themandrel.

If desired, the end turns as well as the intermediate turns of thebacking may be secured to the mandrel by spot welding between the metalof the backing and the shell of the mandrel at certain of or all of thecrests of the corrugations. It is also permissible to use the type ofWelding to be described in connection with subsequent FIG. 8.

A preferred type of securing means as illustrated in FIGS. 1, 4 and 5,comprises U-shaped clips 43 of flattened section which may be single asat 43 in FIG. 4 or of double width as shown at 4312 in FIG. 5 to securetogether portions of the strip to provide a complete loop upon themandrel. Each clip has a leg 48a connected to an intermediate or bightportion and which is adapted to be inserted through appropriate slots oropenings 49 or 49a in the metal of the shell of the mandrel in the landportion 21. As illustrated in the drawing, a single slot is employed foreach clip, one leg of the clip extending through this opening and theother being disposed outside of the end of the shell. If preferred,however, two longitudinally spaced slots or openings may be provided foreach clip and both legs of the clips may then be inserted through theseopenings.

In event that the bands 36 are to be retained as permanent portions ofthe mandrel, it is not precluded to form longitudinally extending slotsas at 36a therein for the reception of the legs of clips. When a turn ofa brush strip crosses the bands at or near these slots, clips may beinserted through the slots to assist in holding the turns in place. Toadmit of accurate position of the clips, to receive the turns, the slotsmay be of a considerably greater length than the width of the sides ofthe clips so that a clip can be peripherally moved to a point where thespiral of the strip will accurately fall between the branches of theclip. Both legs of a clip may be inserted in a pair of slots. It is alsonot precluded to insert one leg of a clip in a slot and to allow theother leg to project outwardly beside the band. This gives furtherflexibility in positioning the clips to receive the turns of the brushstrip. If desired, a pair of clips can then be accommodated in eachslot. As many slots as may be desired may be formed in a iband.

In FIG. 1, three clips are indicated as being equally spaced about theperimeter of the mandrel at the end thereof. Obviously, any otherappropriate number of clips might be employed. For example, if theservice required of the brush is not too heavy, the number of clips maybe reduced to two or even to one. On the other hand, if very heavyservices are required of the brush, the number may be increased asdesired. 'In the drawings, the clips are indicated only at the ends ofthe mandrel. In these positions, they effectively hold the ends of thestrip. Usually, this is sufiicient and clips engaging the intermediateportion of the brush are not required, but their use is not precluded.They may be applied at any point along the length of the strip byappropriately slotting the metal of the lands 21 to receive the legs ofthe clips.

Means to hold the sides of the strip in firm engagement with the sidewall of the channel backing element of the strip are indicated ascomprising screws such as are shown at 5 1 or 51a in FIGS. 4, 5 and 6 ofthe drawings. These screws may be of the conventional selftihreadingtype designed to form their own threads by biting into the metalpenetrated by them. As shown in FIGS. 5 and 7, nuts of the so-calledTinnerman type comprising U-shaped pieces of metal 52 providingself-threading nuts, may also be disposed over one of the legs of theclips and these may be employed to hold the screws in place. In thelatter event, holes for the reception of the screws may be punched orbored in both legs of the clips of a size to permit the screw threads topass without biting into the metal.

In FIG. 7 is illustrated a detailed view of a modified form of clipadapted (for securing at intervals along the length of a brush strip inorder more securely to hold the intermediate turns in place upon amandrel. In this construction, the shell portion of a mandrel isindicated as at 69 and includes longitudinally extending corrugations 61corresponding to the corrugations 2.1. These corrugations, of course,are separated by intermediate webs (not shown). The blanks from whichthe shell of the mandrel is formed may be provided with slots 62distributed along the entire length of the blank. The number of slots soprovided may be substantially greater than are required for thereception of the clips for holding the brush strip in place. This istrue because the thickness of a brush strip tends to vary to a certaiandegree and, therefore, it is difiicult to provide slots which are in allinstances precisely spaced to register with the turns. By increasing thepopulation of slots, the probability of enough turns of the strip cominginto register with a sufl'icient number of slots is increased.

In order further to accommodate for the variation in the spacing of theturns with respect to the slots and also to permit securing U-shapedclips to intermediate turns of the brush strip while operating entirelyfrom the exterior of the mandrel shell, as shown in FIG. 7, appropriateclip holders 63 may be provided.

These holders are mere strips of metal, each having a hooked portion 64adapted to be inserted into an opening 62. The projecting portion of thestrip is bent over upon the top of the corrugation 61 corresponding to acorrugation or land 21, and a turn 65 of the brush strip is woundthereupon to hold the strip in place. A clip 66 of greater width thanstrip 63 and having slots as at 67 in the sides near the bottom thereofis provided, and the end of the strip is inserted through the slots. Aturn 68 of the brush strip is then wound between the branches of theclip and is secured by transverse screw 69 and Tinnerman nut 69a.Insertion of the screw causes the bottom of the brush strip channel tobe pressed against strip holder 63 to grip the latter. The end of theclip holder strip is allowed to project from the side of the clip and isheld down by one or more subsequent turns 68a of the brush strip.

If desired, the clip holder strip 63 may be formed to a length to extendunder several turns of the brush strip, thus increasing the securitywith which the strip is held. The strip 63 may even extend the lengthofthe mandrel shell and a number of clips 66 may be strung thereupon. Aclip may be provided for each turn or they may be provided only forcertain turns, for example, for each third or fourth turn. The ends ofthe strip 63 may be held as shown in slots 62 or, if preferred, they maybe spot welded to the mandrel shell or they may be held by screwsextending through the ends of the strip and the shell. If strips 63 arelong, the intermediate portions thereof may also be secured at intervalsto the shell by spot welding or by self-threading screws. A turn of thebrush strip can then be taken over the top of the weld or screw. Clipholder strips 63 may be spaced at intervals around the mandrel, forexample, at or 120 angles, to obtain balance.

It is an advantage of the clip holder strips that clips thereupon can beslid longitudinally as the brush is wound to accommodate forirregularities of the thickness of or spacing of the 'brush strip turns.

The foregoing system can be used to secure intermediate turns of thestrip, but the end turns of the strip can still be secured as by theclip arrangements illustrated in FIGS. 1, 4, 5, 6 and 7.

In FIG. 8 of the drawing is shown the formation of a slightly modifiedform of brush structure embodying the main principles of the invention.In this construction, spot welding as at W is employed to secure theshell of the mandrel upon the bushings thereof. Also, the backingelement of the 'brush strip is secured at appropriate points along itslength with suitable spots of weld metal applied to the backing and tothe tops of the corrugation of the shell of the mandrel in order toeffect union between the two. In this construction, the corrugated shellhas bushings I01 disposed therein. The bushings are provided withperimetric cylindrical flanges 102 and 103, the latter of which (theouter) is slotted at proper intervals and has portions bent radiallyoutwardly to provide teeth or lugs 134 engaging in the corrugations inorder to provide a positive drive between the bushing and the mandrelshell. A key-way 166 is also formed within the inner perimeters of thebushings in order to receive a key locking the bushings from rotationupon a shaft 167.

A brush strip 198, having fill material 199 secured in a channel backingelement 110 by a core 112 of wire or other material, is secured at oneend to an end of a corrugation of the mandrel shell. Means to effectsecurement of the end turns may comprise U-shaped clips such as havealready been described in connection with FIGS. 1, 4, and 6. Weldingsuch as is to be described, or other menas may also be employed. Theprecise method of securing the end turns of the brush strip is not shownin the figure.

After the end of the brush strip has been secured, the shaft 197 isrotated to wind the brush strip as a spiral upon the mandrel. At all of,or certain of, the points where the strip crosses the corrugations ofthe mandrel, the channel backing element may be secured to the crest ofthe corrugations as by electrical welding. Welding may conveniently beperformed by means of spaced electrodes 113 having conductors 114joining them to an appropriate source of electrical current. Metal forthe weld between the crests of the corrugations and the channel backingelement of the brush strip is applied by a welding rod 115, the tip ofwhich is disposed in or near the are between the tips of the electrodes,whereby to fuse bits of the metal of the rod as gobs or nodules 117,which by union with the metal of the shell of the mandrel and thechannel backing element, provide a bond between the two. As many pointsof welding as may be desired may be pro vided in order to effectivelysecure the brush strip to the mandrel. When the winding and weldingoperation is completed, the brush strip may be severed from the portionremaining unwound. The end of the spirally wound portion of the brushstrip may then be secured to the mandrel to complete the brush.

In FIGS. 9, 10, 11 and 12, are illustrated several dilferent blanks orsheets of metal which have been provided with appropriate corrugations,adapting them to be bent and secured upon suitable bushings to providemandrels, also embodying the principles of the present invention. Asillustrated in the several FIGURES, 9-12, the sheets of metalconstituting the starting blanks are appropriately stamped or rolled toprovide the corrugations while retaining the overall flatness of thesheets. The formation of corrugated units in this manner may beperformed in a factory performing the metal rolling, and the flat unitscan be stacked in small space for shipment to the brush manufacturer,who will then circularize the units and assemble them upon bushings toprovide brush mandrels in the manner already described.

In the construction illustrated in FIGS. 9 and 10, the fiat sheet isrolled or otherwise bent to provide a series of spaced, transversecorrugations 121 having angular corners and being separated byintervening valleys or reverse corrugations 122.

In this construction, the circulation of cooling air through thefinished mandrel may be promoted by the formation of openings 124,either in the corrugations or in the valleys between the corrugations.When the brush is rotated, these openings permit the air impelled bycentrifugal force of rotation to pass outwardly, thus producing acooling action about the channel elements of the brush strip.

In the construction as illustrated in FIGS. 11 and 12, the intermediateportions of a blank 130 are provided with corrugations 131. Thesecorrugations, as shown in FIG. 12, are of semi-circular or otherappropriate section and may be formed in the metal by a stamping orrolling operation. Marginal bands or strips 133 of the blank are leftplain and these marginal portions possess the advantage that they do notstretch or become distorted when the blank is circularized and appliedto the bushing elements. The marginal portions provide convenient zonesfor the insertion of self-threading screws or other fastenings, such asbolts or rivets, securing the mandrel shell to the flanges of thebushings. To this end, the blanks at the time the corrugations areformed may also be provided with holes 134 punched to receive suchscrews, and matching holes may be formed in the perimetric flanges ofthe bushings.

It is an advantage of this construction that the spacing between theholes cannot be altered by the bending operation involved incircularizing the mandrel.

The shells from blanks can be circularized and held upon the bushingswith or without the use of straps such as the straps 36. The overlappedends of the blanks 129 or 130 after circularization of the latter, canbe held together by welding, brazing, self-threading screws, rivets,bolts, or by other devices.

FIG. 14 illustrates a suitable fixture for holding the bushings of amandrel in proper position while the shell is being secured thereupon.

In this construction, a shaft is formed with pairs of appropriatelyspaced detents 141 mounted in radial holes 142 and being resilientlyoutwardly urged by coiled springs 143. The distance between the detentsof a pair is such that they will engage and grip the edges of the innerperimeter of a bushing to hold the same, but will yield to permit thebushings to be slid into place or removed from the shaft at will. Butsingle pairs of detents for each bushing have been illustrated. However,added pairs of detents circularly spaced from these may also be providedin order to assure that the bushings will be held in a plane vertical tothe shaft 149.

Bearings or supports for the shaft are not shown, but may beconventional bearings or spaced brackets, clamps, or other devicesdesigned to hold the shaft by one or both ends while the bushings aremounted and the shell is secured thereupon.

To form a mandrel upon this fixture, bushings are spaced upon the shaftand held by detents 141. The shell of the mandrel is then placed uponthe bushings and is held by bands as at 36. Such screws or otherfastenings as are required may also be inserted at this stage.

When the mandrel is assembled, it may be removed and secured in a lathefor winding the brush strip thereupon. An appropriate chuck structurefor such lathe is illustrated in FIG. 15, as comprising a shaft 15%mounted in bearings (not shown) and being power driven by a motor drive(also not shown). Upon the shaft is disposed a disc-like face plate 152having a coaxially disposed rim 153 with a shoulder 154 providing a stopfor a mandrel shell 20. Lugs 155 are provided upon the rim to projectinto the corrugations of the shell to provide a positive drive for themandrel as the winding of the strip is conducted.

Preferably, two of these chucks, one for each end of the mandrel, areprovided and they are carried upon separate coaxially spaced shafts topermit the mounting or removal of the mandrels as required.

The shaft should be splined as at 156 to permit the face plate to beretracted from the end mandrel, but providing a positive drive betweenthe shaft and the face plate. Means to hold the face plate in positionupon the shaft is illustrated as comprising a set screw 157 threadedthrough a hub portion 153 of the plate. Obviously, other meansreleasably to hold the face plate from retraction from the mandrel maybe employed.

When a brush strip is being wound upon this structure, the ends of themandrel are clamped by the face plates, with lugs inserted in the endsof one or more corrugations. An end of a brush strip is secured at anend turn in the manner already described and the mandrel is slowlyrotated spirally to wind up the strip. If desired, additional fasteningsbetween the strip and the shell of the mandrel are applied as the stripis wound. When in the winding operation the last turn is reached, theend clips or other fastenings are applied to the brush strip and thelatter is out (if an excess is present), thus conipleting the brush. Oneof the face plates may then be released by unscrewing set screw 157 andthe plates can be separated to permit the completed brush to be removedand a new mandrel can be inserted for winding.

A complete brush B is illustrated in FIGS. 13 and 16, and is keyed as atK upon a mandrel M.

I claim:

1. A rotary, power-driven brush comprising a mandrel, which is a sheetof metal constituting a tube, bushings disposed within the tube, saidtube further having slots formed therein and U-shaped clips having bightportions disposed within the tube and legs radially outwardly extendingthrough the slots, the clips being of flattened section, and a brushstrip comprising a channel backing wound about the mandrel, the clipsengaging the turns of the brush strip and means securing the strip inthe clips, said means comprising screws extending through 1e sides ofeach of the clips and engaging the side walls of the channel backing ofthe strip.

2. A rotary, power-driven brush comprising a mandrel, which is alongitudinally corrugated tube and having spirally wound thereupon abrush strip comprising a channel backing element and fill materialdisposed in said channel backing element, and means securing the brushstrip to the mandrel comprising flat metal strips secured to the mandreland extending longitudinally thereof, and U-shaped clips having slotsformed in the sides thereof, the fiat metal strips extending through theslots, said U-shaped clips engaging the side walls of channel backingelement to secure the same to the mandrel.

3. A rotary, power-driven brush comprising a mandrel, which is alongitudinally corrugated tube of sheet metal, the tube being providedwith bushings having teeth elements engaging the corrugations of thetube to provide a positive drive between the bushings and the tube, aband comprising a strip of metal disposed about the tube to hold thesame upon the bushings, a brush strip comprising a channel backing withfill material disposed the-rein, spirally wound about the tube, thebacking of said strip having substantially straight portions across thedepressions formed by the corrugations to impart to the turns ott thestrip the form of a polygon, whereby to prevent rotation of the stripupon the tube under heavy loads.

4. A rotary, power-driven brush comprising a mandrel, which is alongitudinally corrugated tube having spirally wound thereupon a brushstrip comprising a channel backing element and fill material disposed insaid element, said element being secured at each end to thetube and theintermediate portions of the elements, where they cross the depressionsformed by the corrugations of the tube, being substantially straight toimpart to the turns of the strip a polygonal shape, whereby the strip isheld from rotation with respect to the tube when the brush is performingwork.

5. A rotary, power-driven brush comprising a mandrel, which is alongitudinally corrugated tube having spirally wound thereupon a brushstrip comprising a channel backing element and fill material disposed insaid element, said element being secured at each end to the tube and theintermediate portions of the elements, where they cross the depressionsformed by the corrugations of the tube, being substantially straight toimpart to the turns of the strip a polygonal shape, whereby the strip isheld from rotation with respect to the tube when the brush is performingwork, means to secure the strip to the tube comprising U-shaped clipshaving branches extending through slots formed in the corrugations ofthe tube and embracing the sides of the strip, and screws extendingthrough the sides of the clips and engaging 10 the edges oil the channelbacking element to lock the latter in place.

6. A rotary, power-driven brush comprising a mandrel which is a sheetmetal, longitudinally corrugated tube, said tube having bushingsdisposed therein, said bushings having teeth spaced about the outerperimeters thereof and spaced segments of a coaxially extending flange,a segment being disposed between pairs of teeth, said teeth beingdisposed in the corrugations of said tube to provide a positive drivebetween the bushings and the tube, screws extending through the walls ofthe tube and the segments of the flanges upon the bushing-s to securethe bushings in place in the tube, a brush strip having a channelbacking with fill material disposed therein, said st-rip being wrappedabout the tube, and U-shaped clip elements having intermediate bightportions disposed within the tube and having legs extending throughslots formed in the tube and engaging the turns of the strip element tohold the latter in place upon the tube.

7. A rotary, power-driven brush comprising a mandrel which is alongitudinally corrugated tubeof sheet metal, wherein the sides of thecorrugations are substantially spaced, the sheet having overlapped endssecured together and providing a longitudinal scam in the tube, andhaving a spiral brush strip thereupon, said strip comprising a channelbacking element secured to the crests of at least some of thecorrugations, spaced annular bushings disposed in the tube, a pair ofradially projecting teeth disposed at the outer perimeter of each ofsaid bushings and projecting into a pair of contiguous corrugations ofthe tube, the remainder of the perimeter of the bushings being free ofteeth, teach tooth being of dimensions substantially corresponding tothe sect-ion of the corrugation into which it projects, said bushingshaving longitudinally extending, peripheral, outer flange portionsbetween the teeth, and means securing the portions of the tube betweenthe corrugations to the flange portions.

8. A rotary, power-driven brush comprising a mandrel which is alongitudinally corrugated tube of sheet metal, wherein the sides of thecorrugations are substantially spaced, the sheet having overlapped endssecured together by means of screws extending through the overlappedportions and providing a longitudinal seam in the tube, and having aspiral brush strip thereupon, said strip comprising a channel backingelement secured to the crests of at least some of the corrugations,spaced annular bushings disposed in the tube, a pair of radiallyprojecting teeth disposed at the outer perimeter of each of saidbushings and projecting into a pair of contiguous corrugations of thetube, the remainder of the perimeter of the bushings being free ofteeth, each tooth being otf dimensions substantially corresponding tothe section of the corrugation into which it projects, said bushing-shaving longitudinally extending, peripheral, outer flange portionsbetween the teeth, and screws extending through the portions of the tubebetween the corrugations and the flange portions whereby to secure thetube to the bushings.

9. A rotary, power-driven brush comprising a mandrel which is alongitudinally corrugated tube of sheet metal, the sides of thecorrugations being substantially spaced, the tube having a spiral brushstrip thereupon, said strip comprising a channel backing element andfill material disposed in said element, said element being secured tothe crests of at least some of the corrugations, and spaced annularbushings disposed in the tube, said bushings having radially projectingteeth disposed at the outer perimeter thereof, the teeth beingperipherally spaced about the bushings to project into a plurality ofcorrugations of the tube, and each of said teeth being of dimensionssubstantially corresponding to the section of the corrugation in whichit projects, and a band comprising a strip of metal disposed about thetube and having the ends thereof secured together to hold the tube fromexpansion from the bushings, the brush strip further being 11 wound oversaid band, longitudinally extending flange portions at the outerperimeter of each bushing and being disposed between said teeth, andscrews extending through the portions of the tube between thecorrugations and through the flange portions and securing them together.

10. A rotary, power-driven brush comprising a mandrel which is a sheetof metal longitudinally corrugated and providing a tube, the sides ofthe corrugations being substantially spaced with respect to each other,said mandrel having bushings disposed therein, each of said bushingshaving a plurality of radially outwardly projecting teeth of dimensionssubstantially corresponding to the cross-section of the corrugations,the peripheral spacings of the teeth also corresponding to the spacingof the corrugations, and each bushing further having coaxially extendingouter peripheral flange portions disposed between the teeth, screwsextending through the walls of the tube and the flange portions upon thebushings to secure the bushings in place in the tube, a brush striphaving a channel backing and till material disposed therein wrappedabout the tube, and U-shaped clip elements having legs extending throughslots formed in the tube and engaging turns of the strip to hold thelatter in place upon the tube, the bignt portions of the clips beingdisposed within the tube.

11. A rotary, power-driven brush comprising a mandrel which is alongitudinally corrugated tube of sheet metal, the sides of thecorrugations being substantially spaced, the tube having a longitudinalseam therein and having spirally wound thereupon a brush stripcomprising a channel backing element and fill material disposed in saidelement, said element being secured to the crests of at least some ofthe corrugations, and spaced annular bushings disposed in the tube, eachof said bushings having radially projecting teeth disposed at the outerperimeter of the corrugations of the tube and each of the teeth being ofdimensions substantially corresponding to the section of the corrugationin which it projects, and a band comprising a strip of metal disposedabout the tube to hold the tube upon the bushings, the brush stripfurther being wound over said band and longitudinally extending flangeportions at the outer perimeter of each bushing, and being disposed uponeach side of each of said teeth, and screws threaded through the wallsand the flange portions to hold the bushings in place.

12. A rotary, power-driven brush comprising a mandrel, which is a sheetof metal constituting a tube, bushings disposed within the tube, saidtube further having slots formed therein and U-shaped clips having thebight portions thereof disposed within the tube and legs radially 12outwardly extending through the slots, the clips being of flattenedsection, and a brush strip comprising a channel backing wound about themandrel, the clips engaging the turns of the brush strip, and screwsextending transversely of the brush strip through both legs of each ofthe clips and drawing the legs together, thus clamping the brush stripin the clips.

13. A rotary, power-driven brush comprising: (1) a single flexible sheetof metal in the form of a tube, the ends of the sheet being overlappedand means securing the overlapped ends of the sheet together, said sheethaving peripherally spaced, parallel corrugations and inwardlyprojecting web portions therebetween,

(H) a plurality of annular sheet metal bushings disposed inlongitudinally spaced relationship within the tube,

(111) said bushings each having a peripheral flange extending coaxiallyof the tube and engaging said web portions whereby to support the tubein place upon a mandrel, the flange being secured to the bot toms of theweb portions,

(IV) the flange upon a bushing having a notch in an edge thereof and atooth integral with the bottom of the notch and projecting outwardly inthe space Within a corrugation in the tube, and providing a positivedrive between the tube and the bushing, said tooth being of dimensionscorresponding to the cross-sectional dimensions of said corrugation, and

(V) a brush strip having fill material projecting outwardly therefrom,the strip being wound around the tube and being secured thereto.

References Cited in the file of this patent UNITED STATES PATENTS181,524 Dickinson Aug. 29, 1876 612,157 Cook Oct. 11, 1898 642,484Phillips Jan. 30, 1900 1,479,074 McLaughlin Nov. 20, 1923 1,579,182Thayer Mar. 30, 1926 2,285,375 Hansen June 2, 1942 2,379,205 WesemeyerJune 26, 1945 2,651,799 Lombardi Sept. 15, 1953 2,757,401 Peterson Aug.7, 1956 2,824,327 Van Clief Feb. 25, 1958 2,882,815 Bernier Apr. 21,1959 2,907,063 Jones Oct. 6, 1959 2,921,328 Bongiovanni Jan. 19, 19602,977,622 Nelson et a1. Apr. 4, 1961

1. A ROTARY, POWER-DRIVEN BRUSH COMPRISING A MANDREL, WHICH IS A SHEETOF METAL CONSTITUTING A TUBE, BUSHINGS DISPOSED WITHIN THE TUBE, SAIDTUBE FURTHER HAVING SLOTS FORMED THEREIN AND U-SHAPED CLIPS HAVING BIGHTPORTIONS DISPOSED WITHIN THE TUBE AND LEGS RADIALLY OUTWARDLY EXTENDINGTHROUGH THE SLOTS, THE CLIPS OF FLATTENED SECTION, AND A BRUSH STRIPCOMPRISING A CHANNEL BACKING WOUND ABOUT THE MANDREL, THE CLIPS ENGAGINGTHE TURNS OF THE BRUSH STRIP AND MEANS SECURING THE STRIP IN THE CLIPS,SAID MEANS COMPRISING SCREWS THROUGH THE SIDES OF EACH OF THE CLIPS ANDENGAGING THE SIDE WALLS OF THE CHANNEL BACKING OF THE STRIP.